1. Field of the Invention
The present invention relates to a telephone apparatus. More particularly the present invention relates to a telephone apparatus having a function of supplying a reception (called) side with information on a calling (transmitting) side such as telephone number information.
2. Background of the Invention
A telephone service which is called "Call Display" for inserting the telephone number of a calling (transmitting) side between bell signals for reception of a call and transmitting the data to a reception (called) side has widely propagated in the U.S. A and Canada. FIGS. 1A and 1B are diagrams showing a time chart and a format of the reception bell signals transmitted to the reception side.
In this Call Display telephone service, modem data containing information on the telephone number of a calling side is inserted between first and second bell signals as shown in FIG. 1A. A bell signal is used to ring a bell of a telephone at the reception side, and it includes, for example, a 20 Hz signal which is continuous for two seconds (corresponding to one bell sound). The modem data having data length corresponding to four seconds is inserted after 0.5 second elapses subsequently to a first bell signal. Further, a second bell signal is located so as to be continuous for two seconds after 0.5 second elapses subsequently to the modem data. Subsequently, the similar bell signals, each of which is continuous for two seconds, are intermittently transmitted at a time interval of 5 seconds until an user at the reception side answers the call. The modem data is inserted only between the first and second bell signals.
In this case, as shown in FIG. 1B, the modem data includes a synchronizing signal consisting of a repetition of "1", "0" which are alternately repeated over 240 bits at the head of the modem data, and subsequently a signal having a train of "1" (mark) each continuing for 25 msec over 150 msec. This signal is used to identify the head of the data. The modem data finally includes information on month, date, hour, minute and telephone number. This information on month, date, hour, minute and telephone number are respectively set with 144 bits in the U.S.A., and with about 250 bits in Canada. For these modem data, biphase marks codes (mark="1"=2200 Hz, space ="0"=1200 Hz are transmitted at 1200 baud. This is defined as a Bell 202 standard.
According to this telephone service, by decoding the modem data located between the first and second bell signals, the telephone number of a calling side can be detected before a reception side receives and answers the phone from the calling side. In a conventional telephone apparatus, the telephone number of the calling side which is obtained by decoding the modem data as described above is displayed on a display unit such as an LCD (Liquid Crystal Display). Except for a case where the telephone number of the calling side is well known by the user, it is common that the user cannot immediately identify a calling side on the basis of the telephone number of the calling side even when the telephone number is displayed on the display unit.
Accordingly, in addition to the Call Display telephone service, some companies have conducted a service which is called "Name Display".
According to the Name Display telephone service, the name of a telephone subscriber is transmitted together with information on the telephone number thereof between the reception bell signals. However, in order to perform the Name Display telephone service, loads such as installation of a new switchboard, etc. must be imposed on a telephone office side, and thus this service has hardly propagated.
A technique for enabling the display of names of calling sides using only the Call Display telephone service has been previously proposed in U.S. Pat. No. 4,924,496, for example.
According to this technique, a telephone apparatus is equipped with a dictionary memory in which the telephone numbers of calling sides and the corresponding names of the calling sides can be registered. In this telephone apparatus, transmitted information on a telephone number is decoded on the basis of the Call Display telephone service to compare the telephone number data with each of the registered telephone numbers read out from the dictionary memory, and if any telephone number is coincident with the transmitted telephone number data, the name data of the coincident telephone number is read out and displayed on a display unit such as an LCD.
However, in the technique as described above, an user is required to prepare beforehand a dictionary memory containing name data corresponding the telephone numbers of calling sides. That is, it is necessary that the user manually inputs these names and registers the names in correspondence with the telephone numbers. This task is very formidable and imposes a large burden on the user, and thus this telephone apparatus is inconvenient for the user.
Further, this telephone service must use a display unit having an alphabetical-letter displaying function, and it is expensive.